Since the 1970's, adverse health effects have been reported at unexpectedly low concentrations of particulate air pollution, leading scientists and public health officials to conclude that long-term exposure to combustion-related fine particulate air pollution is a significant environmental risk factor for heart and lung diseases. Despite numerous studies examining the effects of petroleum diesel (petrodiesel) exhaust emissions on the respiratory system, the mechanisms responsible for the reported adverse human health effects and which features of the particles initiate adverse processes remain elusive. Biodiesel fuel made from vegetable oil or animal fat is gaining momentum as the energy source of the future both in the U.S. and Europe. Biodiesel is typically blended into conventional diesel fuel, and emission testing has shown that biodiesel emissions contain reduced levels of hydrocarbons, carbon monoxide and particulate matter (PM) but a higher concentration of soluble organic fraction. The hypothesis to be tested is that particulates from biodiesel combustion will have less adverse lung effects compared to those from petrodiesel. The biological effects will include cell death and compensatory cell growth and inflammatory responses, regulated by the activation of the Mitogen-activated Protein Kinase (MAPK) and Nuclear Factor-kappa B (NF-(B) signaling pathways in human lung epithelial cells and macrophages in vitro and an in vivo murine inhalation model of lung injury. Cot (cancer osaka thyroid and rat homologue, tumor progression locus 2 or Tpl2), a human proto-oncogene, is a serine/threonine kinase in the MAP Kinase kinase kinase (MAPK3K) family that is expressed in hematopoietic and lung tissues. COT/Tpl2 has been shown to induce ERK1/2 and NF-(B and play a role in T cell activation. We plan to test whether particulates from petro- and biodiesel combustion will differentially activate COT/Tpl2 and subsequently differentially activate ERK1/2 and NF-(B pathways leading to characteristic cytokine/chemokine responses and a shift in the balance between cell apoptosis and proliferation. The data to be obtained in this proposal will lay the groundwork for future studies aimed at identifying the specific components of exhaust emissions that lead to lung injury and the potential interventions that may attenuate the pathogenic responses. PUBLIC HEALTH RELEVANCE: Biodiesel has been touted as an important strategy for energy independence as well as sustainability in terms of agricultural production and reduced environmental impact from the transportation sector, but as with petrodiesel, combustion of biodiesel produces particulate air pollution. Adverse health effects have been reported at unexpectedly low concentrations of particulate matter in air pollution, leading scientists and public health officials to conclude that long-term exposure to combustion-related particulate air pollution is a significant environmental risk factor for heart and lung diseases. Despite the belief that biofuels may be better for the environment and for human health, there is very limited information about the biological and health effects of biodiesel emissions so this project will compare and contrast the biological effects of emission particles from the combustion of petro- and biodiesel in an effort to lay the groundwork for future studies aimed at elucidating the mechanisms responsible for the significant relationship between airborne particulates and lung and heart disease and at developing approaches to reduce the adverse health consequences of air pollution.